When I see a candidate is not sure about some syntax trivia e.g. indexing expressions in Python, names for some library functions like charAt, size, length etc. I tell them to pick one (make it up) and move on. Though lately I've been using a runnable whiteboard with autocomplete so they have been able to figure it out on their own.

It makes me sad to think how hard it would be to remove bad interviewers like above. But as long as they perform reasonably well they won't get fired, and I don't think there is any interview QC system to feed back into the org. And thus we slowly slide from A to B and C territory...